In order to manufacture a semiconductor integrated circuit device, various complicated processes may be performed on a wafer. Accurate information managements of the semiconductor integrated circuit device by units may be performed.
In order to manage the information, a semiconductor manufacturing company may provide the wafer, which may be delivered from a wafer manufacturing company, with a laser mark for identifying kinds of circuits in the wafer or LOT numbers. The wafer, which may be processed by a same manufacturing system, may be processed by a single LOT unit by a same process so that the information managements may be readily performed by the laser mark including the LOT numbers.
The laser mark may be formed by irradiating a pulse laser to an edge portion of the wafer. The laser mark may have a dot matrix structure. The laser mark may include an identification number of the semiconductor manufacturing company.
However, when forming the laser mark, particles may be attached to the wafer. The particles may cause a non-uniform thickness of the wafer in an etching process. Further, the particles may cause scratches in a polishing process.